Signal lamp



FIG. 1 is a front perspective view of a signal lamp showing my new design;

FIG. 2 is a front side view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a top view thereof

FIG. 6 is a bottom view thereof; and,

FIG. 7 is a rear view thereof. 

The ornamental design for a signal lamp, as shown and described. 